WASHINGTON — Chanting "Kill the bill," thousands of conservatives rallied at the Capitol on Thursday against the Democrats' health care overhaul plan.

The campaign-style event kicked off a daylong, Republican protest against the legislation.

"This bill is the greatest threat to freedom that I have seen," House Republican leader John Boehner of Ohio told the crowd gathered on the lawn near the West Front of the Capitol.

Said Rep. Steve King, R-Iowa: "We're not going to leave this Hill until we kill this bill."

Among the signs in the crowd was one reading, "Waterboard Congress," and another saying, "Vote no to government-run health care." The crowd included a significant number of older Americans.

Some conservatives oppose increased government involvement as the first step on a slippery slope to "socialized" medicine, a term they use to denigrate other countries' health care systems, and insist on rugged American individualism, in which people should be responsible for their own health care.

In addition, millions of Americans get health care from their employers and are reluctant to see any tinkering with that system.

House Majority Leader Steny Hoyer predicted the bill will be passed in the House on Saturday. It is aimed at extending coverage to tens of millions of uninsured Americans and banning the medical insurance industry from turning people away. The Senate is working on its own bill, which will have to be reconciled with the House bill for final legislation.

Hoyer told reporters House leaders would have the 218 votes needed to pass the sweeping bill that President Barack Obama has made the defining social goal of his young administration — presuming a couple of final issues are resolved. Hoyer acknowledged that the vote could be tight.

"I wouldn't refer to it as a squeaker, but I think it's going to be close," Hoyer said. "This is a huge undertaking."

Obama praises supportPresident Obama also weighed in on Thursday in a rare appearance at the White House briefing. He trumpted endorsements from the AARP and the American Medical Association of House Democrats' legislation.

Obama told reporters that those endorsement are no small accomplishments. He urged Congress to listen to the AARP and AMA and pass the health care overhaul.

Video: Obama: 'Pleased' at AARP, AMA support
Obama says AARP, the nation's premier lobbying group for the elderly, has looked at the bill and is supporting it in the interest of seniors. He also says the AMA wouldn't be supporting the bill it if would lead to health decisions being made by government bureaucrats or damage doctor-patient relationships.

But while the House bill is moving, action is slower on the other side of the Capitol, where senators are awaiting a cost analysis from the Congressional Budget Office on Senate legislation written by Senate Majority Leader Harry Reid and others. The timeline there appears likely to spill into next year, posing difficulties for the Obama administration.

"We certainly have well over 218 people who say they want to vote for the bill," Hoyer said in an interview with wire service reporters. That is a majority in the 435-member House.

Obama also planned a rare trip to the House on Friday to try to win over wavering lawmakers.

Potential stumbling blocksWith no Republican backing, Democrats will need overwhelming support from within their own caucus. An intraparty disagreement over how to prevent federal funds from being used to pay for abortion has not yet been entirely resolved, though Hoyer said that language being circulated by one anti-abortion Democrat seemed likely to be the basis for an agreement.

House leaders are also still grappling with illegal immigration, specifically whether illegal immigrants — who would be barred from getting federal subsidies — should be able to purchase insurance coverage within new government "exchanges," using their own money.

The White House does not want this allowed, but some members of the Congressional Hispanic Caucus and other Democrats view that position as too extreme.

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